In the space industry, spacecraft such as satellites are positioned in space for a number of different purposes including, for example, collecting and/or communicating data, information and the like. To effectively operate, however, the attitude of these satellites, including the satellites' azimuth and elevation angle, must typically be stabilized. One method to stabilize the attitude of a satellite is to set it in a spinning motion. Being in an otherwise uncontrolled environment, however, a number of different objects and/or events can disrupt a satellite's attitude, and accordingly, disrupt proper operation of the satellite. To determine, and thus enable control, of a satellite's attitude, a number of satellites include star trackers that image a fixed astronomical object, such as a star, as the satellites spin. From the imaged object, the star tracker is capable of determining the current attitude of the satellite. Then, if the current attitude is offset from the desired attitude of the satellite, the satellite can be controlled to reposition itself to the desired attitude.
One conventional technique for a star tracker to image a star is referred to as time-delay integration (TDI) imaging. In accordance with such a technique, a frame transfer element generates a continuous image of a fixed star, considered moving relative to a spinning satellite. The frame transfer element typically generates the continuous image via a stack of linear arrays of imaging elements, such as charge-coupled devices (CCDs), aligned with and synchronized to the movement of the star. Accordingly, as the image of the star moves from one line to the next, the stored charge moves along with the image, thereby providing a higher-resolution image at low light levels.
Although a number of different star scanners operating in accordance with TDI imaging techniques have been developed, it is generally desirable to improve upon such conventional devices.